Search found 193 matches

by Jim Leff
Tue Jan 02, 2024 11:34 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Rocket Transits Rippling Moon (2024 Jan 02)
Replies: 6
Views: 2239

Re: APOD: Rocket Transits Rippling Moon (2024 Jan 02)

Whether shock waves or heat, the unanswered question is whether it’s tied to the rocket launch, or some broader condition.
by Jim Leff
Fri Sep 22, 2023 4:13 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Cosmos in Reflection (2023 Sep 22)
Replies: 13
Views: 3633

Re: APOD: Cosmos in Reflection (2023 Sep 22)

Don’t miss the photographer’s two minute making -of video (linked in the APOD text) which gives great context plus a witty reference to the “Three Body Problem” sci-fi trilogy: https://www.youtube.com/watch?v=3Pbr2wIgCHE
by Jim Leff
Tue Sep 12, 2023 12:05 pm
Forum: The Communications Center: Breaking Science News
Topic: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars
Replies: 21
Views: 32430

Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Thanks, Ann. Not that different from Anton Petrov‘s central point, but a lot more meaty. And I’m looking forward to that Bayesian analysis (though I don’t expect a gangbuster for MOND therein).
by Jim Leff
Thu Aug 24, 2023 6:28 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Meteors along the Milky Way (2023 Aug 24)
Replies: 11
Views: 2637

Re: APOD: Meteors along the Milky Way (2023 Aug 24)

Friends all over the world shared my feeling that this one was a bust. I didn’t make it all the way till 4, but from 12-2, I spotted only a handful per hour, even from a very dark position.

When I was a kid, meteor showers were spectacular! These skies today……..
by Jim Leff
Mon Aug 21, 2023 4:59 pm
Forum: The Communications Center: Breaking Science News
Topic: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars
Replies: 21
Views: 32430

Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

So what it's really about is a pretty high hurdle that MOND proponents are going to have to pass before many people take them seriously. OTOH, I don't see anyone impugning Kyu-Hyun Chae or his university. No one crying bullshit. So while I in no way would have imagined open-armed acceptance of this...
by Jim Leff
Sun Aug 20, 2023 7:53 pm
Forum: The Communications Center: Breaking Science News
Topic: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars
Replies: 21
Views: 32430

Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Ann wrote: Sun Aug 20, 2023 5:19 am ParallaxNick claimed that another study of wide binaries had come to the conclusion that Newtonian gravity can explain the orbital motion of these stars extremely well.
Wasn’t that precisely the contrast Petrov offered in his video?
by Jim Leff
Sat Aug 19, 2023 11:56 pm
Forum: The Communications Center: Breaking Science News
Topic: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars
Replies: 21
Views: 32430

Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Yes, as I suggested above, it’s “just the slow wheels of science, everyone aware but awaiting replication, etc?”
by Jim Leff
Fri Aug 18, 2023 3:42 pm
Forum: The Communications Center: Breaking Science News
Topic: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars
Replies: 21
Views: 32430

Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

I have a friend who is into all sorts of pseudo science stuff who keeps pushing me to watch Anton Petrov videos. Is he actually legit?
by Jim Leff
Thu Aug 17, 2023 10:34 am
Forum: The Communications Center: Breaking Science News
Topic: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars
Replies: 21
Views: 32430

Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Even if it holds up, it probably doesn't mean that we don't still need dark matter to explain our observations. But let me interject some deep scientific knowledge I’ve acquired (by looking up MOND on Wikipedia ): The fact that some form of unseen mass must exist in these systems detracts from the ...
by Jim Leff
Tue Aug 15, 2023 9:33 pm
Forum: The Communications Center: Breaking Science News
Topic: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars
Replies: 21
Views: 32430

Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Ah, ok, gotcha.

Is it odd not to hear more chatter about this, or is it just the slow wheels of science, everyone aware but awaiting replication, etc?
by Jim Leff
Tue Aug 15, 2023 8:13 pm
Forum: The Communications Center: Breaking Science News
Topic: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars
Replies: 21
Views: 32430

Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Thanks, Ann.

I hope it’s not just hype!

Looks like I posted this in the wrong section. Maybe if it’d been posted in “news” it’d have drawn more comments..
by Jim Leff
Thu Aug 10, 2023 12:18 pm
Forum: The Communications Center: Breaking Science News
Topic: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars
Replies: 21
Views: 32430

Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

New paper in Astrophysical Journal, via phys.org "Smoking-gun evidence for modified gravity at low acceleration from Gaia observations of wide binary stars". A new study reports conclusive evidence for the breakdown of standard gravity in the low acceleration limit from a verifiable analys...
by Jim Leff
Sun Aug 06, 2023 6:07 pm
Forum: The Communications Center: Breaking Science News
Topic: SA: A Background ‘Hum’ Pervades the Universe. Scientists Are Racing to Find Its Source
Replies: 1
Views: 13315

SA: A Background ‘Hum’ Pervades the Universe. Scientists Are Racing to Find Its Source

Published by Scientific American on Friday Astronomers are now seeking to pinpoint the origins of an exciting new form of gravitational waves that was announced earlier this year In June, a new era in astronomy began with the apparent discovery of low-frequency gravitational waves, the ambient hum ...
by Jim Leff
Thu Feb 23, 2023 11:45 pm
Forum: The Communications Center: Breaking Science News
Topic: 1st observational evidence linking black holes to dark energy
Replies: 4
Views: 772

Re: 1st observational evidence linking black holes to dark energy

Over my head. Is this interesting?

I'm not claiming to have extracted the most salient quote.
by Jim Leff
Thu Feb 23, 2023 11:42 pm
Forum: The Communications Center: Breaking Science News
Topic: 1st observational evidence linking black holes to dark energy
Replies: 4
Views: 772

1st observational evidence linking black holes to dark energy

1st observational evidence linking black holes to dark energy University of Hawaii News February 15, 2023 With singularities absent, the paper then shows that the combined vacuum energy of black holes produced in the deaths of the universe’s first stars agrees with the measured quantity of dark ene...
by Jim Leff
Tue Jan 24, 2023 1:55 pm
Forum: The Communications Center: Breaking Science News
Topic: Earth’s Core Rotation Halting/Reversing
Replies: 0
Views: 1481

Earth’s Core Rotation Halting/Reversing

Original report: https://www.nature.com/articles/s41561-022-01112-z.epdf Pop science boil-down: https://www.vice.com/en/article/xgyje7/earths-core-has-stopped-and-may-be-reversing-direction-study-says I always figured the core (or at least the molten metal surrounding it) spun faster than this. For ...
by Jim Leff
Thu Jul 14, 2022 12:38 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Webb's First Deep Field (2022 Jul 13)
Replies: 103
Views: 34309

Re: APOD: Webb's First Deep Field (2022 Jul 13)

These images are, I suppose, false-colour representations of infrared data. Which, in turn, seems to contradict the rather fussy replies I got earlier this year when I asked ( http://asterisk.apod.com/viewtopic.php?p=320630#p320630 ) whether Webb output could be usefully depicted in visible spectru...
by Jim Leff
Wed Jul 13, 2022 6:18 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Webb's First Deep Field (2022 Jul 13)
Replies: 103
Views: 34309

Re: APOD: Webb's First Deep Field (2022 Jul 13)

These images are, I suppose, false-colour representations of infrared data. Which, in turn, seems to contradict the rather fussy replies I got earlier this year when I asked ( http://asterisk.apod.com/viewtopic.php?p=320630#p320630 ) whether Webb output could be usefully depicted in visible spectru...
by Jim Leff
Sun Mar 13, 2022 9:37 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Quarter Moon Shadow
Replies: 2
Views: 3061

Re: Quarter Moon Shadow

Doh! Of course! Thanks!
by Jim Leff
Sun Mar 13, 2022 4:00 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Quarter Moon Shadow
Replies: 2
Views: 3061

Quarter Moon Shadow

Why does the termimator on a quarter moon look straight? If the earth is round, shouldn't its shadow be round?
by Jim Leff
Sun Feb 13, 2022 7:24 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Visible Light Extrapolation from Infrared Imaging
Replies: 10
Views: 4801

Re: Visible Light Extrapolation from Infrared Imaging

It is indeed possible to classify stars just based on their infrared properties. So I guess this means we'll at least know enough to add, for instance, a broadly red glow to red stars if we want to make some nodding effort to interpret Webb's infrared images for human-visual. It's not much (more ak...
by Jim Leff
Sun Feb 13, 2022 7:20 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Visible Light Extrapolation from Infrared Imaging
Replies: 10
Views: 4801

Re: Visible Light Extrapolation from Infrared Imaging

Regardless of your intent, the imaging is in a different part of the spectrum. There simply isn't the data required to know what's going on in the shorter wavelengths for anything other, perhaps, than stars. Intent was something you brought up, not me. I simply asked whether it was possible. You ch...
by Jim Leff
Sun Feb 13, 2022 1:25 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Visible Light Extrapolation from Infrared Imaging
Replies: 10
Views: 4801

Re: Visible Light Extrapolation from Infrared Imaging

“Useful” is an odd word choice. If I’m to take that literally, you’re brusquely dismissing something I and others might like to see, as if our interests are irrelevant while yours are paramount. If you mean scientifically useful, then you’re misunderstanding my inquiry despite multiple clarification...
by Jim Leff
Sat Feb 12, 2022 11:05 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Visible Light Extrapolation from Infrared Imaging
Replies: 10
Views: 4801

Re: Visible Light Extrapolation from Infrared Imaging

Hmm, thanks for the answer, but the "interested in trying" part threw me a little. I don't think(?) you're denying it would be ideal if some of its output were extrapolatable into visible light, thus making it more accessible for human eyes. If that output could be post-processed to deligh...